Servomotor and valve device



April l0, 1951 E. A. RocKwELL SERVOMOTOR AND VALVE DEVICE 2 Sheets-Sheet 1 Original Filed April ll, 1941 INVENToR Bv, Q i. L

ATroRNE April 10, 1951 E. A. ROCKWELL 2,548,495

SERVOMOTOR AND VALVE DEVICE Original Filed April ll, 1941 2 Sheets-Sheet 2 INVENTOR ATTOR N Patented pr. 10, 1951 SERVOMOTOR AND VALVE DEVICE Edward A. Rockwell, Cleveland, Ohio Application February 17, 1943, Serial No. 476,245, now Patent No. 2,388,220, dated October 30, 1945, which is a division of application Serial No. 388,003, April 11, 1941, now Patent No. 2,398,252, dated April 9, 1946. Divided and this application October 28, 1944, Serial No. 560,865

1s claims. (c1. so-54.5)

My invention relates particularly to a valve apparatus designed for use with a servomotor in such a manner as to be applicable to the operation of many different types of apparatus, but which may, for example, be especially applicable to the operation of power units for controlling automobiles, airplanes, etc.

The present application is a division of my application upon Valve Apparatus, Ser. No. 476,245, filed February 17, 1943, Patent No. 2,388,220, granted October 30, 1945, which in turn is a division of my application upon Power Intensifier Valve, Ser. No. 388,003, filed April 11, 1941, Patent No. 2,398,252, granted April 9, 1946.

The object of my invention is to provide an apparatus of the above character in which the servomotor valve arrangement is provided to effectively control the inlet of differential pressures for the operation of power units of the above character. VA further object in this' connection, is to effectively control the application of a vacuum applied in connection therewith. Still a further object is to control the application of the same in connection with an adjustable opening or venting means. Further objects of my invention will appear from the detailed description of the same hereinafter.

While my invention is capable of embodiment in many different forms, for the purpose of illustration I have shown only one form thereof in the'accompanying drawings in which- Fig. 1 is a longitudinal section of the apparatus made in accordance with my invention;

Fig. 2 is a vertical section taken on line 2 2 of Fig. 1, showing the relative location of the valveoperating lever and diaphragm valves operated thereby; I

Fig. 3 is a detailed section showing the mounting of said valve-operating lever taken on line 3-3 of Fig. 2; and

Fig. 4 is a'vertical section, enlarged, of the air inlet device showing the air inlet valve in its open position when taking in air.v

Referring lto the drawings, I have shown a flexible discharge conduit I6 which leads to a screw-threaded tting Ilia on a power unit I1, said power unit l1 having a ilexible discharge pipe i8 which leads by any desired branch pipe to wheel cylinders I9 located on the four wheels of the automobile chassis (not shown) so as to operate the usual brake shoes 29 and 2| provided in connection with all of said wheels for cooperating with brake-drums (not shown) thereon. The said pipe I8 is connected by a screw-threaded tting 24 to a plunger housing 25 of the power unit, said housing having projections 26 and 21 carrying studs 28 and 29 as well as nuts 30 and 3| to hold in place tightly clamping members 32 and 33 which are arranged to be clamped around a steering column 34 of the automobile chassis.

Also secured to said plunger housing' 25 there is a rear shell 35 secured in place by screws 36. The said rear shell 35, by means of screws 31, clamps in place a main diaphragm 38 against a forward shell 39 which has a screw-threaded sleeve 4l] secured thereto an which communicates by a fitting 4i with a flexible pipe 42 which leads to a manifold 43 of theinternal combustion engine mounted on said chassis for driving the automobile. The sleeve 40 contains a check valve 43a, for trapping and maintaining the highest available vacuum and, therefore, making it possible to utilize the highest differential pressures, provided with peripheral notches 43D and having a cylindrical valve 43e cooperating therewith. This is in order to maintain as far as possible, for the power unit, a supply of the highest differential of pressures comparable to the atmosphere by the most effective degree of vacuum available from the pipe 42. Y

The liquid forced manuallyout of the master cylinder 5 and received by -the power unit l'l from the pipe I8, enters through a coupling member 44 in said plunger housingA 25 into a valve chamber 45@ This chamber 45 has a peripheral recess 45a. into which there is sprung a liquid distributor plate 45h having near the edge thereof a marginally arranged series of notches 45o to distribute the force of the incoming liquid, thus avoiding undesirable impact on the inlet valve. The initial operation of the brakes by the manual force applied, causes the liquid to ow into a chamber 4B in a plunger 4l having ports 48 leading to a cylindrical chamber 49. The plunger 4l has a U-shaped rubber seal 59 and carries within the same a valve stem 5I having a head 52 thereon, beneath which there is a rubber gasket 53 arranged to act as a compensating inlet valve, the seat for which is a shoulder 54 on the plunger 4l, so that when thus seated the hydraulic liquid, which in the initial operation of the apparatus is conveyed from the cylinder 49 by a port 55 to a pressure'cylinder 59 and thence to the brakes through the pipe I8, is cut 01T by said valve 53, 54 so as thereafter to apply the power from the power unit. It will be noted that the valve stem 5l serves as a supporting guide for the plunger 4l which is reciprocable to some extent on said valve stem. The movementV of the plunger to the right, in Fig. 1, is limited j 3 by a stop 51 formed on the interior of the coupling 44 and the movement of said plunger 4l to the left of said figure is limited by a plunger sleeve 58 which is screw-threaded on the said stem 5I.

The plunger sleeve 53 has thereon a plunger '39 and an annular rubber seal 6|). The said plunger 59 operates in a cylindrical chamber 6| which carries a coil spring 32 normally forcing the plunger 53 to the right so as .to unseat the valve 53, 54, which when open compensates the liquid on the two sides of the valve. The other end of said spring 62 rests against a sleeve 63 located tightly in the end of the chamber 6|, said sleeve having a cap ring '64 and a leather gasket 65 around a rod-shaped plunger S3 carried within a bushing Si within the sleeve 63. The said rod-like plunger 36 bears atl its rear end against the plunger 33 and at its forward end bears against the end of a Valve-operating lever |53, which in turn operates a spring 69 located around a guide rod 10 having a screw-threaded reduced end 1| passing through plates 'i2 and 13 clamped around an opening 'i4 on the diaphragm 38, where it is held in'. place by a nut Y15. The plates 12 and 13 are secured together by screws 13a at the periphery thereof and screws 13b located on opposite sides of a laterally offset portion lc of the plate 12. The said lever t3 is supported by a pivot 16, which can be placed at any dey sired point along said lever to obtain the desired lever ratio, on a rod 11 having a screwthreaded end 18 passing through the plate 13 to which it is tightly held by a nut 13. The other end of the lever 38 has a pivot 33 by means of which it is pivotally connected to a'valve-operu ating sleeve 3| screw-threaded on a valve stem 82 having a vacuum or outlet valve head 83 connected thereto and which carries within the same a rubber washer 84. The said rubber washer seats upon an annular valve seat 85 vwhich is clamped to a subsidiary diaphragm 83 supported by screws 31 and a clamping ring 88 from the plate 12. This clamping to the diaphragm St is accomplished by means of a clamping plate 83 held in place by a valve sleeve 33 screw-threaded to the annular valve seat 85. A coil spring 3i bears at one end against the clamping plate 89 and at the other end against the plate 13 so as to normally force the valve sleeve 90 to the left of Fig. l and thus seat a rubber washer 92 of an air valve or inlet valve e3 against an annular valve seat 94 carried in the plate i3. lt will be noted that the valve sleeve 9@ has air ports S5 leading from within the sleeve to the interior of the shell 35. The air which is admitted to the interior of the shell 35 through the valve 94 is received from openings 96 communicating with a chamber S1 between the plates 12 and 1,3, said opening 93 being provided in a screw-threaded plug 38, having a leather gasket 93a, passing through the plates i2 and 13. A hollow plunger 99 is screw-threaded to the plug 93 which has a central passageway |30 communicating with a longitudinal passageway |ll| in the plug 38. This hollow plunger Se clamps the plate 'i3 against a shoulder |32 on the said plug 38. Ports |33 in the said plunger 3S communicate with a chamber i 31e in the said plunger housing 25 which has an air ventv |35 leading to the outer air. The charnber 3| is also connectedto said vent |35 by a passageway |86 located between the chambers 6| and |34.' The said chamber |04 has a screw plug |01 which merely lls an opening |33 used for convenience in drilling the pasageway itt.

Furthermore, the said chamber |34 has a bushing |39 and outside the same aA sleeve H3, which is tightly carried within the chamber |34. The end of the sleeve is screw-threaded to a cap |i| which acts as a stop in the movement of the plate i3 and also serves to hold in position a leather seal H2 against the outside of the hollow plunger 99. Within the hollow plunger 99 there is a rod H3, operating in an air transfer passage ||3a, the rear end of which rod is screw-threaded into a plug H. acting as a closure for the cylindrical chamber 53. On the forward end of said rod |3 there is a head l5 holding in place a washer H3 which acts as a support for a spring'i around the rod I3, the other end of said spring being supported against a headed sleeve H which in turn rests against a shoulder H9 in the hollow plunger 99. The said headed sleeve ||8 carries a washer ||9a and, furthermore, is screw-threaded to a plunger stem |23 passing through a guiding sleeve |2| held in place in the chamber 5E by a screw |22. The said plunger |29 carries rubber seals |23 and |24 between which there is carried a coil spring |25 on the plunger stem |29, which in turn has a plunger head |25 adjacent to the rubber seal |24, which exerts a pull induced by the diaphragm 33 to place the liquid in the chamber 53 under increased pressure due to the relative sizes of the diaphragm 33 and the plunger |26.

In assembling the power unit it will be understood that the diaphragm 38, plates 'E2 and 'Eli and the valve elements together with the operating lever 63 mounted thereon, can be made into one assembly and the plunger mechanism made into another assembly and that these two assemblies can then be assembled together while at the same time securing the shells 35 and 39 thereto.

In Fig. 4 I have shown an air inlet device in which there is provided means for adjusting the amount of air admitted at diierent altitudes, having correspondingly different barometric pressures, at which the automobile is operated and so as to control the outlet pressure of the apparatus. In this figure I have shown connected to the air vent port |35. a screw-threaded tube |21 having a flared portion |28 provided with a ilange |29 against which there is clamped a rubber diaphragm |30, having a central aperture |3|, by means of screws |32 passing through the diaphragm into said flange |29 and passing through a ange |33 on an air valve housing |34 provided with air ports |35. The upper portion of the housing |34 has a screw-threaded opening |36 through which there is arranged to pass an adjusting screw |31 provided with knurled head |38. On the screw |31 there is a lock-nut |39 so as to holdin place above the housing |34, an air lter shell |40 filled with horse hair and which has a depending rim |4| so arranged as to leave an annular air inlet |42 between the same and the flanges |29 and |33. The adjusting screw |31 has a rounded lower end |43 which is received in a recess |44. in an air valve plate |45 having a downwardly directed rim |46, the air valve plate |45 beingpressed upwardly into a stationary position unaffected by the air and vacuum by a compressed spring |41 which is supported at its lower end on a shoulder |48 within the tube |21. The rim |46 is arranged toY be adjusted into or out of contact with the diaphragm |30 so as to provide an air passageway |49 between the valve plate |45 and said diaphragm |30. The diaphragm |30 is supported in its uppermost position by a supporting ring |50 which is dished upwardly so -as to receive a coil spring seated at its lowerend on a shoulder |52 in the inside of the flared portion |28 of the tube |21. When operating the automobile at high altitudes the spring |5| will be in its position of full extension with the plate |45 adjusted out of contact with the diaphragm |30,' whereas at lower altitudes or where the output pressure applied to the brakes is to be lessened, the plate |45 will be adjusted into contact with the diaphragm |30 so as to compress the spring |5| more or less, as desired, according to the position of the screw |31. However, whether or not such control is initially present, the operation of the power unit will open the passageway |49 more or less according to the suction applied from the pipe |21.

In the operation of the apparatus, when it is desired to apply the brakes some of the liquid from a master cylinder (not shown) passes from the pipe |6 through the valve chamber 45, ports 48, port 55,l chamber 56 and pipe |8 to the wheel brake cylinders |9 so as to move the brake shoes 20 and 2| up into position, for applying the main braking effect. A further increase of this manual pressure from the pipe |6 will cause the piston 59 to move forwardly in the chamber 6|, thus closing the valve 53, 54 and simultaneously operating the lever 68 so as to move the valve 83 into closed position while moving forwardly, slightly, the plates 12 and 13 as well as the diaphragm 38 through the intermediary of the spring 69.- Further increase of the manual pressure, resulting in further movement of the plunger rod 66 in this direction, results in opening the air inlet valve 93 due to the further movement of the lever 68 and the yielding of the diaphragm 86. The opening of the valve 93 admits the air to the desired extent from the vent |05, ports |03, chamber |00, passageway |0I, ports 96 and thence to within the rear diaphragm shell 35 on the right of the diaphragm 38. This exerts a hydraulic pressure in the chamber 56 which, by its reaction, has a tendency to move the diaphragm 38 in the opposite direction to its direction of movement by the manual force applied. The eifect of this incoming air fromthe valve 93 is balanced between said valve 93 and the diaphragm 96 so as to prevent the valve 93 from being suddenly opened by said incoming air. It will be noted, furthermore, that the air may be admitted, in this way, to the chamber within the shell 35 in any desired increments and that between the accession of such increments to the right of the diaphragm 38 the two valves 83 and 93 will be in lapped or closed position due to the pneumatic pressure, above referred to, tending to move the diaphragm 86 downwardly in Fig. 3 in any one position of power application in which the pedal is held. In other words, as the diaphragm 58 moves to the left, in Fig. l, the pivot 16 is carried thereby, and upon cessation of movement of the pedal I, while the valve 93 is still open, the diaphragm 38 will still continue to move to the left slightly as the left hand end of the plunger |06 is then a stationary pivot. At this time, also, a slight movement of the lever 68 aiects the valves 83 and 93, to move them into lapped position. Consequently, the said valves can apply a modulated degree of pressure to the right side of the diaphragm 38, as desired. Similarly, the air may be withdrawn by increments in the same manner from the right of the diaphragm 38 through the opening of the valve 83 to'V Ithe desired extent for this purpose, by lessening the pressure exerted manually. When the atmospheric air pressure has been admitted to the desired extent to the right of the diaphragm 38, this action will be accompanied by the movementof the hollow plunger 99 to the left in Fig. l against the compressionof the spring ||1 so that the plunger head |26 will move to the left in said gure, thereby placing the liquid which is in the chambers 56 and 49 under a pressure to the extent desired and as determined by the manual pressure, thus applying the power pressure through the pipe |8 to the brakes and exerting the reaction from the chambers 56 and 49. This pressure exerted on the brakes may be of any desired maximum but may, for example, be about 1500 lbs. per square inch, whereas the manual pressure applied from the master cylinder may, for example, be from 0 to 600 lbs. per square inch, or any other ratio of these or other pressures can be obtained, as desired. In view of the fact that liquid from the master cylinder is directly connected to and takes part in the movement of the brake shoes 20 and 2|, the said diaphragm produces the desired power pressure on the brakes with a very short path of travel of the manual means and which obviously is a shorter path of travel than would be the case if the brake shoes 20 and 2| were moved only by the air pressure acting on the diaphragm 38. Because of this arrangement, in which the foot always performs a part of the work by supplying a part of the liquid used in applying the brakes, even when the power is being applied about 40% of the liquid in applying the brakes is provided by the foot pressure. This is owing to the fact that the volume received in the right hand end of the bore in which the plunger 41 slides is smaller than the volume delivered by the pipe |8, thus providing for a small pedal travel. In fact, at times the foot pressure applied to the brakes can be increased without substantially moving the foot forwardly. Thus, an effective modulation of the pressures applied to the brakes is obtained at all times, by the manual pressure or the manual pressure and the power pressure proportionally thereto. However, in this power unit, whatever force is supplied manually is entirely offset by an equal and opposite force from the power piston |20 so that, consequently, all the brake-applying force for operating the brakes, when the power is on, is derived entirely from the power plunger |20. This apparatus is thus a full power unit. For these reasons, also, the brake is practically as effective, irrespective of considerable variations in the vacuum from the manifold, due to the direct connection just referred to and the large size of the diaphragm 38. Also, the diaphragm |30 acts as a check valve in such a manner that when the maximum power pressure in the pipe |8 has been applied by the operation of the diaphragm 38, added pressure can be applied by increasing the manually applied pressure in the pipe I8 without substantially moving the piston |26 to the right in Fig. 5, inasmuch as the diaphragm |30 will seat upwardly on the valve seat |49, thus trapping and slightly increasing the air pressure in the pipe |05. It will be noted accordingly that, after the vacuum valve 83 is closed and the air valve 93 is opened it still is possible to have independent movement for further intensifying the pressures, while avoiding retraction of the diaphragm 38. Furthermore, it will be noted that at all times a reaction passes `from the liquid applied in the operation of the `brakes back to the foot, through the pipe I6, either from the liquid in the chamber 49 through the valve 53, 54 when this valve is open, or from the chamber 49 on the plunger 41 when said valve is closed, thereby making the degree of application of the brakes readily ascertainable without the pedal being moved towards its oiT position. Also, the actuation of the brakes is made more effective by reason oi the coordination of the travel of the manual means to the movement of the brakes, as it will be evident that the movement of the brake liquid is coordinated to the travel of the liquid supplied from the master cylinder. In order to throw the brakes out of operation, the manual pressure is fully released, whereupon the spring 60 opens the valve 83 and allows the valve 93 to close the springs H1 and |25 withdraw the diaphragm 30 to the right, thus admitting vacuum thence through the ports 95 to the right of the diaphragm 38. This action is accompanied by the unseating of the valve 53, 54, thus restoring the parts again to their original positions and compensating for any possible loss of liquid in the power unit, ready for the application of the brakes as desired.

In the form of air inlet apparatus as shown in Fig. 4, the adjusting screw |37 is arranged to adjust the air inlet plate |45 to any desired position according to the altitude at which the automobile is operating or the barometric pressure and according to the amount of the maximum output pressure desired to be applied to the brakes. In other words, when the automobile is operating at a high altitude, with consequent lessened atmospheric pressure, the plate |45 will be adjusted upwardly to a position away from Contact with the diaphragm |30, so as to compensate for the entry of air at the lessened barometric pressures, in order to more nearly approximate uniformity in the air supply or to increase the maximum brake pressure. Under these circumstances, therefore, the length of the spring 5| is such as to leave the diaphragm |30 out of Contact with the plate |45. When, however, the automobile is operating at a lower altitude, or when it is desired to decrease the maximum available pressure output supplied to the brakes, the plate |45 will be adjusted downwardly by the screw |31 until it contacts with the diaphragm |30 or until, by further adjustment, it compresses the spring |5| to the point desired` Of course, when the apparatus is being operated to apply pressure to the brakes, the

- incoming air will in any case move the diaphragm |30 downwardly so as to pass through the air inlet |62, ports |35, passage |49 and thence into the tube |27, thus applying to the diaphragm |30 the desired degree of the vacuum exerted at the right of the diaphragm 38, Fig. l. When the valve plate |45 has been adjusted into contact with the diaphragm |30, the incoming air pressure will, of course, move the diaphragm |30 downwardly by compressing the spring |5|. Of course there will be some difference in the downward movement of the diaphragm |30 according to the degree of vacuum on the diaphragm 38 in Fig. l. The compressed spring 4'| merely presses the air valve plate |45 upwardly against the adjusting screw |37.

It will be understood that instead of supplying a vacuum to the fitting 4| this may be a vent and that instead of the port |05 being a vent this may be connected to a source of superatmospheric air pressure.

WhileI have described my invention above ,in detail I wish it to be understood that many changes may be made therein without departing from the spirit of the same.

I claim:

1. A power mechanism, comprising an inlet in the power mechanism adapted to be connected to a source of pressure differing from the atmospheric pressure, a chamber, a conduit connecting said source to the chamber, a check valve in said conduit adapted to admit and maintain substantially the highest difference from atmospheric pressures supplied from said source to the chamber, a movable wall in said chamber adapted to be moved, for the performance of Work, by said pressure differing from the atmosphere, manually controlled valve means for controlling the application of said pressure to the movable wall, a normally closed vent, a passageway connecting the vent to said chamber, and an adjustable pressure-responsive device connected to the vent passageway and constructed to be responsive to changes in pressure in said passageway tending to open said vent upon decrease of the pressure differing from the atmosphere and movably operable independently of said manually controlled means to adjust `by pre-selection the amount of air admitted and the consequent eiectiveness of the said pressure in moving said wall.

2. A power mechanism, comprising an inlet in the power mechanism adapted to be connected to a source of pressure differing from the atmospheric pressure in the form of a vacuum, a chamber, a conduit connecting said source to the chamber, a check yvalve in said conduit adapted to admit and maintain substantially the highest difference from atmospheric pressures supplied y from said source to the chamber, a movable wall in said chamber adapted to be moved, for the performance of work, by said pressure differing from the atmosphere, manually controlled valve means for controlling the application of said pressure to the movable wall, a normally closed vent, a passageway connecting the vent to said chamber, and an adjustable pressure-responsive device connected to the vent passageway and constructed to be responsive in changes in pressure in said passageway tending to open said vent upon decrease of the pressure diiering from the atmosphere arranged in the form of a diaphragm venting valve responsive to inlet and outlet pressure differences in said passageway to adjust the amount of air admitted and the consequentV eiectiveness of the said pressure in moving said wall.

3. A power mechanism, comprising an inlet in the power mechanism adapted to be connected to a source of pressure differing from the atmospheric pressure in the form of a vacuum, a chamber, a conduit connecting said source to the chamber, a check valve located at said chamber adapted to admit and maintain substantially the highest difference from atmospheric pressures supplied from said source to the chamber, a movable wall in said chamber adapted to be moved, for the performance of work, by said pressure differing from the atmosphere, manually controlled valve means for controlling the application of said pressure to the movable wall, a normally closed vent, a passageway connecting thevvent to said chamber,v and an adjustable pressure-responsive device connected to the vent passageway and constructed to be responsive to changes in pressure in said passageway tending to open said vent upon decrease of the pressure differing from the atmosphere arranged in the form of a venting valve comprising a diaphragm and a stationary valve seat, responsive to inlet and outlet pressure differences in said passageway and retractible according to the air pressure applied thereto by said passageway, to adjust the amount of air admitted and the consequent effectiveness of the said pressure in moving said wall.

4. A power mechanism, comprising an inlet in the power mechanism adapted-to be connected to a source of pressure differing from the atmospheric pressure in the form of a vacuum, a chamber, a conduit connecting said source to the chamber, a check valve located at said chamber adapted to admit and maintain substantially the highest diierence from atmospheric pressures supplied from said source to the chamber, a movable wall in said chamber adapted to be moved, for the performance of work, by said pressure differing from the atmosphere, manually controlled valve means for controlling the application of said pressure to the movable wall, a normally closed Vent, a passageway connecting the vent to said chamber on the other side of the movable wall from said conduit, and a valve in said passageway connected to the vent passageway and constructed to be responsive to pressure differences in said passageway due to said vacuum tending to open said vent upon decrease of the pressure diiering from the atmosphere and movably operable independently of said manually controlled valve means.

5. A power mechanism, comprising an inlet in the power mechanism adapted to be connected to a source of pressure differing from the atmospheric pressure in the form of a vacuum, a chamber, a conduit connecting said source to the chamber, a check valve located at said chamber adapted to admit and maintain substantially initially the highest difference from atmospheric pressures supplied from said source to the chamber and thereafter remain seated to trap and maintain substantially the highest admitted pressures, a movable wall in said chamber adapted to be moved, for the performance of work, by said pressure differing from the atmosphere, manually controlled valve means for controlling the application of said pressure to the l movable wall, a normally closed vent, a passageway connecting the vent to said chamber on the other side of the movable wall from said conduit, and a valve in said passageway connected to the vent passageway and constructed to be responsive to pressure differences in said passageway due to said vacuum tending to open said' vent upon decrease of the pressure differing from the atmosphere and movably operable independently of said manually controlled valve means.

6. A power mechanism, comprising an inlet in the power mechanism adapted to be connected to a source of pressure diiering from the atmospheric pressure, a chamber; a conduit connecting said source to the chamber, a check valve located at said chamber adapted to admit and maintain substantially the highest difference from atmospheric pressures supplied from said source to the chamber, a movable means in said chamber adapted to be moved, for the performance of work, by said pressure differing from the atmosphere, manually controlled valve means for controlling the application of said pressure to the movable means, a normally closed vent, a passageway connecting the vent to said chamber on the other side of the movable means from said conduit, a .Valve in said passageway connected to the vent passageway and constructed to be responsive to atmospheric pressures tending to open said Vent upon decrease of the pressure differing from the atmosphere and to pressure differences in said passageway, and means to adjust by preselection manually theeffectiveness of the said pressure in moving said means.

'7. A power mechanism, comprising an inlet in the power mechanism adapted to be connected to a source of pressure differing from the atmospheric pressure in the form of a vacuum, a chamber, a conduit connecting said source to the chamber, a check valve located at said chamber adapted to admit and maintain substantially the highest difference from atmospheric pressures supplied from said source to the chamber, a movable means in said chamber adapted to be moved, for the performance of work, by said pressure differing from the atmosphere, a manually controlled valve means for controlling the application of said pressure to the movable means, a normally closed vent, a passageway connecting the vent to said chamber on the other sideof the movable means from said conduit, and a valve in said passageway responsive to said vacuum, in the form of a diaphragm venting valve connected to the Vent passageway constructed to be responsive to inlet and outlet pressure differencesin said passageway to adjust the amount of air admitted and the consequent effectiveness of the said pressure in moving said means tending to open said vent upon decrease of the pressure diiering from the atmosphere and movably operable independently of said manually controlled valve means. I f

8. A power mechanism, comprising an inlet in the power mechanism adapted to be connected to a source of pressure differing from the atmospheric :pressure in the form of a vacuum, a chamber, a conduit connecting said source to the chamber, a check valve located at said chamber adapted to admit and maintain substantially the highest difference from atmospheric pressures supplied from said source to the chamber, a movable means in said chamber adapted to be moved, for the performance of work, by said pressure differing from the atmosphere, manually controlled valve means for controlling the application of said pressure to the movable means, a'normally closed vent, a passageway connecting the vent to said chamber on the other side of the movable means from said conduit, and a valve in said passageway responsive to said vacuum, in the. form of a diaphragm venting valve connected to the vent passageway and .constructed to be yresponsive to inlet and outlet pressure differences in said passageway, tending to opensaid vent upon decrease of the pressure differing from the atmosphere, said diaphragm being retractible according to the air pressure applied thereto, to adjust the amount of air admitted and the consequent effectiveness of the said pressure in moving said means. n

9. Apower mechanism, comprising an inlet in the power mechanismadapted to ,be connected to a source of pressure differing from the atmospheric pressure in the form of a vacuum, a chamber, a conduit connecting said source to the chamber, a check valve located at said chamber adapted to admit and maintain substantially the highest difference from atmospheric pressures supplied from said source to the chamber, a movable means in said chamber adapted to be moved,

nfor the performance of work, by said pressure differing from the atmosphere, manually controlled valve means for controlling the application of said pressure to the movable means, a normally closed vent, a passageway connecting the vent -to said cham-ber on the other side of the movable means from said conduit, and a valve in said passageway responsive to differences in said vacuum, in the form of a spring-supported diaphragm venting valve connected to the vent passageway and constructed to be responsive to inlet and outlet pressure differences in -said passagewaytending to open said vent upon decrease of the ypressure differing from the atmosphere, to manually adjust the amount of air admittedv and the consequent effectiveness of the said pressure in moving said means.

10. A power mechanism, comprising an inlet in the power mechanism adapted to be connected to a source of pressure differing from the atmospheric pressure in the form of a vacuum, a chamber, a conduit connecting said source to the chamber, a check valve located at said chamber adapted to admit and maintain substantially the highest difference from atmospheric pressures supplied from said source to the chamber, aI movable means in said chamber adapted to be moved, for the performance of work, by said :pressure diiering from the atmosphere, manually controlled' valve means for controlling the application of said pressure to the movable means, a normally closed Vent, a passageway connecting the vent to said chamber' on the other side of the movable means from said conduit, and a manually adjustable valve in said passageway responsive to said' vacuum, in theform of a springsupported diaphragm venting valve connected to the vent passageway and constructed to be responsive to inlet and outlet pressure differences in said passageway, tending to open said vent upon decrease 4of the pressure diiering from the atmosphere, said diaphragm being retractible according to the air pressure applied thereto by said passageway, to manually adjust the amount of air admitted and the consequent eiectiveness atmospheric pressure, a chamber, a conduit connecting said source to the chamber, a check valve located at said chamber adapted to admit and maintain substantially the highest difference from atmospheric pressure supplied from said source to the chamber, a movable means in said chamber adapted to be moved, for the performance of work, by said pressure diiering from the atmosphere, manually controlled valve means for controlling the application of said pressure to the movable means, a vent, a passageway connecting the vent to said chamber on the other side of the movable means from said conduit, and a valve in said passageway constructed to be responsive to atmospheric pressures and to pressure differences in said passageway, sa-id valve having a stationary spring-supported valve member and an adjusting screw for said member.

12. A power mechanism, comprising an inlet in the power mechanism adapted to be connected to a source of pressure diiering from the atmospheric pressure in the form of a vacuum, a chamber, a conduit connecting said source to the chamber, a check valve located at said chamber adapted to admit and maintain substantially the highest pressures supplied from said source to the chambena movable means in said chamber adapted to be moved, for the performance of work; by said pressure differing from the atmosphere, manually controlled valve means for controlling the application of said pressure to the movable means, a vent, a passageway connecting the vent to said chamber on the other side of the movable wall from said conduit, and a valve in said passageway constructed to be responsive to pressure differences in said passageway due to said vacuum, said valve comprising a diaphragm having an annulus supporting the same, a stationaryY valve seat cooperating with said diaphragm and concentric coil springs supporting said annulus and seat respectively.

13. A power mechanism, comprising an inlet in the power mechanism adapted to be connected to a source of pressure diiering from the atmospheric pressure, a chamber, a conduit connecting said source to the chamber, a check valve located at said chamber adapted to admit and maintain substantially initially the highest difference from atmospheric pressures supplied from said source to the chamber and thereafter remain seated to trap and maintain substantially the highest admitted pressures, a movable means in said chamber adapted to be moved, for the performance of work, by said pressure diiering from the atmosphere, manually' controlled valve means for controlling the application of said pressure to the movable means, a vent, a passageway connecting the vent to said chamber on the other side of the movable means from said conduit, and a valve in said. passageway constructed to be responsive to atmospheric pressures and to pressure difierences in said passageway, said valve comprising a stationary spring-supported valve member and an adjusting screw for said member.

14. A power mechanism, comprising an inlet in the power mechanism adapted to be connected to a source of pressure differing from the atmospheric pressure in the form of a vacuum, a chamber, a conduit connecting said source to the chamber, a check valve located at said chamber adapted to admit and maintain substantially initially the highest difference from atmospheric pressures supplied from said source to the chamber and thereafter remain seated to trap and -maintain substantially the highest admitted pressures, a movable means in said chamber adapted to be moved, for the performance of work, by said pressure diiering from the atmosphere, manually controlled valve means for controlling the application of said pressure to the movable means, a vent, a passageway connecting the vent to said chamber on the other side of the movable wall from said conduit, and a valve in said passageway constructed to be responsive to pressure dierences in said passageway due to said vacuum, said valve comprising a diaphragm having an annulus supporting the same, as well as a stationary valve seat cooperating with said diaphragm and concentric coil springs supporting said annulus and seat respectively.

l5. A power mechanism, comprising an inlet in the power mechanism adapted to be connected to a source of a relatively lower pressure, a chamber, a movable wall in said chamber, adapted to be moved, for the performance of work, by said pressure, a hydraulic intensifier piston connected to the movable wall, a manually movable means movable against the force exerted by the movable wall, a hydraulically controlled valve means movable by said manual means for controlling the application of said pressure to the movable wall to operate the intensifier piston, an opening leading to a relatively higher pressure, a passageway connecting the opening to said chamber, and a check valve associated with the movable wall and the intensifier piston and arranged to seat in order to prevent the intensifier piston from being moved when further manual pressure is applied by the manual means after said rst mentioned pressure has been applied to the movable wall.

16. A power mechanism comprising an inlet in the power mechanism adapted to be connected to a source of pressure diiering from the atmospheric pressure, a chamber, a conduit connecting said source to the chamber, a check valve in said conduit, a movable wall in said chamber, adapted to be moved, for the performance of work, by said pressure differing from the atmospheric pressure, a hydraulic intensier piston connected to the movable wall, a manually movable means movable against the force exerted by the movable wall, a hydraulically controlled valve means movable by said manual means for controlling the application of said pressure to the movable wall to operate the intensier piston, a vent, a vent passageway connecting the vent to said chamber and a check valve in said vent passageway arranged to be seated to trap the air on the higher pressure side of the movable wall so as to retain the air in the vent passageway and thereby prevent the intensier piston from being moved when further manual pressure is applied by the manual means after said pressure, differing from the atmospheric pressure, has been applied to the movable wall.

17. A power mechanism comprising, means for applying power including a power motor, a piston connected for operation by the motor and a piston cylinder for producing a hydraulic pressure, an outlet connection from said means for the performance of work, an inlet connection for applying a range of manual pressure to Said means capable of exceeding the pressure produced. by the power means, and means inclufh ing a fluid valve associated with said piston, arranged and constructed to prevent the retraction of the power actuated piston when the manual pressure exceeds the power applying pressures, said manually applied pressure and power applied pressures being hydraulically connected together.

18. A power mechanism comprising, means for applying power including a power motor, a piston connected for operation by the motor and a piston cylinder for producing a hydraulic pressure, an outlet connection from said means for the performance of work, an inlet connection i for receiving a range of manual pressure to said means capable of exceeding the pressure produced by the power means, means for applying to said inlet connection a manual pressure exceeding a power applying pressure, and means including a fluid valve associated with said piston, arranged and constructed to prevent the retraction of the power actuated piston when the manual pressure exceeds the power applying pressures, said manually applied pressure and power applied pressures being hydraulically connected together.

EDWARD A. ROCKWELL.

appearances orrnn l The following references are of record in the ile oi' this patent:

UNITED STATES PATENTS Number Name Date 102,390 Morton Apr. 26, 1870 1,403,290 Catching Jan. 10, 1922 1,653,985 Campbell Dec, 27, 1927 1,770,194 Bragg July 8, 1930 1,809,014 Bragg June 9, 1931 1,826,417 Bragg Oct. 6, 1931 1,887,750 Bragg Nov. 15, 1932 2,252,482 Gates Aug. l2, 1941 2,260,490 Stelzer Oct. 28, 1941 

